Well cover for machine tool



www mn 7 @nm Wmf 1A E. A. DUNNING WELL COVER FOR MACHINE TOOL Filed Aug. 1. 1960 May 21, 1963 E. A. DUNNING WELL covER Foa MACHINE Toon Filed Aug. 1, 1960 2 Sheets-Sheet 2 I nverzfof United States Patent O ware Filed Aug. 1, 1960, Ser. No. 46,579 Claims. (Cl. 90-S8) This invention relates to improvements in machine tools and especially to devices for preventing the fouling of machine parts wh-ich are located in wells where metal chips, drillings and the like will fall during the operating of the machines. More especially the invention provides means for covering wells, slots or ways provided in the mountings of such machines. Such mountings sometimes enclose the means which reciprocate the work bearing tables.

In machine tools, such as milling, drilling and boring machines at least one, and usually two rectilineally movable tables are provided upon which the object to be operated upon'is fastened. For positioning or manipulating the object, the table is arranged to be propelled back and forth upon ways formed below the table in the base of the machine, or when a second table is used, an upper table may be similarly mounted upon the lower table. In either case the base or supporting part which comprises the ways, also may comprise a box like structure or well which serves partially to enclose certain operating means which are sought to be protected from fouling. However these wells have a longitudinal slot in the top through which a bracket or extension on the bottom of the table projects for operatively connecting the movable table with ways, traversing mechanism and the like. The slot permits extraneous matter to fall within the wells, and means are desired in order to avoid fouling the operating mechanism for this source;

Heret'ofore, one means of protecting operating parts in such wells was to bridge the slot with a sectional cover or screen comprising a series of rectangular tabs joined or hinged to each other. Covers thus formed were attached to the leading and following edges of the table and arranged -to slide in ways formed in the parallel margins of the slot. Thus the arrangement covered the portions of the slot not covered by the table as the table was reciprocated. A device of this kind excludes most of the dirt from the wells, but in operation it isunsatisfactory in that the ways in the margins of the slot and the joints of the sectional cover becomes clogged with metal chips unless constant and time consuming attention is given toward cleaning and maintaining the covers in operation. Another device comprises a cover composed of a thin fiat rectangular strip of resilient metal which is mounted in shoulders or ledges cut in the margins of the slots so that the surface of the cover and the top of the table are in the same plane. An opening or eye is provided in a way bearing bracket or nut bracket which projects from the table downwardly into the well. The opening through the nut bracket is positioned to elevate or hump the ilat strip progressively above the level of the table as the table is reciprocated. The unperforated part of the bracket extends around the strip. The strip is fastened to the base at its ends and stressed. Rollers are mounted to and underneath the table on either side of the humped cover so as to progressively depress the cover into the shoulders along the slot and ilush with the surface of the table. This device also covers the slot temporarily, but small and progressively larger particles of extraneous matter gradually work into the shoulders or ledges along the slot and impair the operation and effectiveness of this device, unless meticulous and frequent attention is given to cleaning debris from the shoulders. Undulations also 3,090,284 Patented May 2l, 1963 "ice tend to form in the at stressed strip beyond the range of the depressors through which extraneous matter may freely by-pass the cover. While these and other devices lhave been proposed for the purposes described, they have left much to be desired, and more effective devices are sought which will require a minimum of attention to maintain them in suitable operating condition, and without constant personal attention.

' In accordance with the present invention a slot in the top of a well is closed by a cover or guard which is an elongated, specially formed resilient strip which -is self reformable when deformed desirably, but not necessarily composed of metal, such as spring steel. The cover is transversely arched, providing edgewise downwardly eX- tending legs along the longitudinal margins of the cover, which seat along narrow lines on the surface of the table, or desirably upon a pair of cushion-like or seating strips mounted in the top of the table beside the margins of t-he slot, so that the sealing line will be removed somewhat from the margins of they slot. The cover is fastened at its ends to prevent endwise movement, and is passed through an eye formed in a bracket which extends downwardly from underneath the table and located so that the guard will be elevated above the surface of the table, to provide clearance for a suiciently strong connection between the mechanism in the well and the table. Depressors are provided underneath the table to compress the edges of the down-struck legs onto'their seats. The arched guard thus formed provides a longitudinally stiffened structure beyond the margins of the table in all its positions. The arched structure also provides a non-buckling member which can be variably compressed upon its longitudinal seats, thereby promoting vits sealing functions. Underneath the table where the arched cover is bumped to pass through the eye, a minimum of effort is required for this purpose, as there is a flattening of the strip somewhat. The resilient material thus formed is self reformable which promotes its function as a self servicing device.

One of the objects of the present invention is to provide an effective covering for slots of openings in the tops of wells of machine tools of the kind described.

Another object is to provide such a covering which does not require constant or frequent servicing to maintain it in effective operating condition.

Other objects will become apparent from the following description of various embodiments of the invention which are made with reference to the drawings, in which FIG. l is a top plan View of a drilling machine, showing only 4one reciprocating table mounted on the base, and with the slot in the base provided with a protective cover made in accordance with the prevent invention,

FIG. 2 is a partial side elevational and partial cross sectional view of the device of FIG. 1 taken along the line II-II of FIG. l, showing in detail -a nut bracket and lmeans to elevate the cover and pass it through an' eye in the upper part of the bracket,

FIG. 3 is a partial end elevational a-nd partial cross sectional view taken along the line III-III of FIG. 2 showing an end View of the bracket and cover in elevated position passing through the eye of the bracket,

FIG. 4 is a partial end elevational and partial cross sectional view taken along the line IV--IV of FIG, 2, showing the Idisposition of the parts when the guard is in lowered position, both before and after it is passed through the eye of the bracket,

FIG. 5 is a transverse cross sectional view of a cover v such as that shown in FIGS. 1 to 4 with its obliquely and outwardly projecting longitudinal edge portions contacting the surface of the table,

FIG. 6 is -a transverse cross sectional view of a guard which is arcuately arched ,and is in longitudinal contact with cushions or contact members mounted beside and along each margin of the slot,

FIG. 7 is a view of a guard similar to that of FIG. 6 in which the intermediate portion of the -arched cover is at, Y

FIG. 8 is another modification of the arched cover in which -the intermediate portion of the arch is additionally reinforced and stifened by -being corrugated, and

FIG. 9 is a cross sectional view of stil-l another modication of the cover in which the intermediate portion of the arch is hat.

FIG. 10 is a sectional view taken along the line X-X of FIG. 2.

Referring to FIGS. l and 2 of the drawings, the machine tool, such as a boring machine has a reciprocating table 1 upon which the article to .be bored or operated upon is mounted. The means for operating upon the object or boring tools (not shown) are carried by a turret having an upright or post 12 which extends upwardly from the base of the machine. The table 1 is arranged to be reciprocated on ways 3 and 4 which are formed in the base 2 of the machine. Where a second or upper table is also used, the latter is similarly mounted on the lower table to operate at right angles to table 1.

The portion of base 2 underneath the table I1 comprises a box like structure forming au enclosure or Well 5 within which the table operating mechanism, such as the traversing screw 6 may be mounted. The traversing screw is driven lby suitable means, such 'as the hand wheel 7 mounted on its outer end, thereby to cause the table to be reciprocated upon its ways. The ibox like structure or well 5 in the base is closed at its top directly underneath the table 1, except a rectangular slot 8 (FIG. 2) which opens upwardly and through which the nut :bracket 9 is mounted to extend downwardly. The nut bracket 9 is mounted in an `axial position on the bottom of the table 1 so that it will travel through the longitudinal slot 15. At the lower end of bracket 9 a traversing nut is mounted to engage the traversing screw 6, so that upon turning the screw one way or the other the table will be moved in a desired direction.

The slot 8 is closed by the rectangular 'guard or cover 10 which may desir-ably be an elongated thin strip of `formed spring steel. The guard is fastened at its ends to the base 2 by cap screws v11 which are set flush with rthe exposed surface of the guard. This prevents endwise movement of fthe guard. The cover is passed through the eye of the nut bracket 9 in parallelism with the margins ofthe slot. The eye 15 is located in the bracket 9 so that the cover 10 is bumped and raised above the level of the table top suiciently to clear the portions of the nut bracket which pass :around 'the edges of the cover and to the point of attachment of the bracket underneath the table.

An elevating means which operates to hump the cover locally and progressively as the table is moved in either direction, comprises lau elevator |bracket 16 mounted at one end Ion the upper part of the bracket 9 to swivel up and down, and at the other end to carry a transversely disposed pin 17 upon the ends of which rotatable Contact members 18 or wiper lugs are disposed to press upwardly on the lower surface of the cover 10 and raise the cover so that the bracket will be cleared. Means for adjusting the height of the elevators and for retaining them in the adjusted position may comprise a spring 19 mounted on the footing 20 and biased against the elevator bracket 16. Instead of a spring other retaining and adjusting means, such as an adjusting screw may be mounted on the footing 20 to upwardly bear against the bracket 16. Alternatively, one or more wipers may be mounted on or made integrally with the bracket 9 instead of the rollers 12, but for elevating the cover, rollers are desirable. The bracket 9 may be any bracket which extends downwardly from the Vbottom of .the table, such as the elongated bracket 9' or rail which carries the Way slide at its lower end. For mounting a cover over such a well or elongated opening, a clearance for the cover may be provided between the table 1 and the top members of the base near the bracket.

Underneath the table 1 and intermediate the humped portion of the cover 10 and the leading and following edges 21 and 22 of the table 1, the wiping depressor members, or bosses 23 and 24 (FIG. 2) are mounted in any suitable manner for contacting the top surface of the slot cover 10, so that the Vedges of the cover which project from the leading and following edges of the table will press firmly upon the top of the base along and beside the margins of the slot 8, or upon the sur- -faces of the cushionsor footings 31 which are mounted in the channels 26 formed in the top surface of the base beside the margins of the slot.

The well covers 10 are elongated members desirably composed of spring steel, but votherinaterial of somewhat similar resiliency may be used. VIn a preferred form a flat steel elongated strip is bent over along its longitudinal edges to form outwardly and obliquely disposed down struck legs 30. The legs 30 (FIGS. 1 and 4) are seated on cushions 31 which are secured within channels 26 in the :top of Ithe wall of the rwcll and parallel with Vthe margins of the slot. The down struck legs of the cover tend to depressv more or less the footing or cushioning material 25, depending upon the adjustment of the depressors 23 and 24, the resiliency of the footing material and the longitudinal stiffness of the arched cover. The idepressors 23 and 24 are adjusted so that the contacts along the edges ofthe cover are tirm in all instances. This results in a tendency to depress the surface of contact, or cushioning material, depending on the firmness of the contact material and upon the stiffness of the longitudinally disposed stiifening means of the cover. A r-m grade of neoprene has been found to ibe a satisfactory footing material, as it has a desirable cushioning eifect and resistance to oil, but other materials having more or less resiliency may be used. Metal to metal contact may also be used as illustrated in FIG. 5, but a cushioning effect is desirable as it admits of the use of somewhat less pressure on the -top of the cover and less transverse flexing of the cover in order to maintain effective sealing along the edges.

FIG. 5 illustrates a preferred form of the transversely arched cover and a metal to metal contact, but a pre- -erred contact arrangement is illustrated in FIGS. 6 to 9 wherein cushioned footings are mounted on the base. The cover maybe arcuately arched as shown in FIG. 6, instead of being in the form of a at arch. Various forms of down struck legs may also be used, such as the longitudinally disposed rounded edging of FIG. 7, or the rectangular edging of FIG. 9. Additional reinforcement of the arched strip intermediate its legs is illustrated in FIG. 8, in which longitudinal corrugations 32 are incorporated. In this modification the contact poi-nts for the depressors and elevator means should be selected either along the plain surfaces at the side of the corrugations, or if elsewhere, the corrugations must present a suitable longitudinal area along which the forme-d depressors and elevators pass. In the modification shown in FIG. 8, the depressor arrangement of FIG. 2 and the elevator arrangement of FIG. 3 may be used, but depressors and elevators of other -form mlay be used.

From the foregoing description it will be recognized that the invention is capable of still other modifications from those specifically shown, without departing from the spirit and scope thereof; iand it is to be understood that the disclosure may not be construed as limiting the invention to the specific illustrations set forth herein.

I claim:

1. In a machine tool, a movable table upon which to secure objects to be worked upon; a mounting for said table comprising walls having a top surface, said walls being disposed to provide a well having longitudinal edges forming a slot opening upwardly from said wall, said movable ltable being mounted to move over rand above the said top surface of the wall; a cover spanning said slot for excluding extraneous material from said well; said cover being an elongated, resilient, self-reforming, stii, transversely arched member which is formed with down struck legs along its longitudinal edges, said down struck legs forming at their lower extremities sealing means spaced from and along the longitudinal edges of the slot; a bracket secured to said table .mounted to extend downwardly into said slot, said bracket having an opening therein @above the level of said top surface for threading said cover longitudinally therethrough and causing the cover to rise locally above lthe level of said surface; means for fastening the ends of the cover to said mounting for preventing endwise movement of the cover; and depressor means bearing downwardly on either side of said bracket and on por-tions of the top of said cover for vertically positioning said legs in seated and sealing engagement with said ltop surface and spaced from and on opposite edges of the slot said depressor being disposed to depress said portions of the cover until the same are compressed and transversely flexed to space said longirtudinal edges of the downstruck legs outwardly from said seated engagement.

2. A device in accordance with claim 1 in which the Walls have a pair of channels in lthe top thereof which are located on either side of, separated from and parallel with the margins of the slot; and resilient means mounted lin said slots which are engaged Iby the downstruck legs of the cover.

3. A device in accordance with claim 1 in which the cover comprises longitudinally disposed cormgations intermediate the legs thereof.

4. A device in accordance with claim 1 in which the arched cover comprises an intermediate section which is hat.

arched cover comprises an intermediate section which is arcuate.

UNITED STATES PATENTS References Cited in the le of this patent 1,669,504 Baker May 15, 1928 1,937,985 Schnuck Dec. 5, 1933 2,190,213 Meyer Feb.l 13, 1940 2,227,404 Zimmermann Dec. 31, 1940 2,303,438 Cornelius Dec. 1, 1942 2,465,399 Robinson Mar. 29, -l949 5. A device in accordance with claim 1 in which the 

1. IN A MACHINE TOOL, A MOVABLE TABLE UPON WHICH TO SECURE OBJECTS TO BE WORKED UPON; A MOUNTING FOR SAID TABLE COMPRISING WALLS HAVING A TOP SURFACE, SAID WALLS BEING DISPOSED TO PROVIDE A WELL HAVING LONGITUDINAL EDGES FORMING A SLOT OPENING UPWARDLY FROM SAID WALL, SAID MOVABLE TABLE BEING MOUNTED TO MOVE OVER AND ABOVE THE SAID TOP SURFACE OF THE WALL; A COVER SPANNING SAID SLOT FOR EXCLUDING EXTRANEOUS MATERIAL FROM SAID WELL; SAID COVER BEING AN ELONGATED, RESILIENT, SELF-REFORMING, STIFF, TRANSVERSELY ARCHED MEMBER WHICH IS FORMED WITH DOWN STRUCK LEGS ALONG ITS LONGITUDINAL EDGES, SAID DOWN STRUCK LEGS FORMING AT THEIR LOWER EXTREMITIES SEALING MEANS SPACED FROM AND ALONG THE LONGITUDINAL EDGES OF THE SLOT; A BRACKET SECURED TO SAID TABLE MOUNTED TO EXTEND DOWN-WARDLY INTO SAID SLOT, SAID BRACKET HAVING AN OPENING THEREIN ABOVE THE LEVEL OF SAID TOP SURFACE FOR THREADING SAID COVER LONGITUDINALLY THERETHROUGH AND CAUSING THE COVER TO RISE LOCALLY ABOVE THE LEVEL OF SAID SURFACE; MEANS FOR FASTENING THE ENDS OF THE COVER TO SAID MOUNTING FOR PREVENTING ENDWISE MOVEMENT OF THE COVER; AND DEPRESSOR MEANS BEARING DOWNWARDLY ON EITHER SIDE OF SAID BRACKET AND ON PORTIONS OF THE TOP OF SAID COVER FOR VERTICALLY POSITIONING SAID LEGS IN SEATED AND SEALING ENGAGEMENT WITH SAID TOP SURFACE AND SPACED FROM AND ON OPPOSITE EDGES OF THE SLOT SAID DEPRESSOR BEING DISPOSED TO DEPRESS SAID PORTIONS OF THE COVER UNTIL THE SAME ARE COMPRESSED AND TRANSVERSELY FLEXED TO SPACE SAID LONGITUDINAL EDGES OF THE DOWNSTRUCK LEGS OUTWARDLY FROM SAID SEATED ENGAGEMENT. 